The oil and gas industry utilizes check valves for a variety of applications, including oil and gas wellbore operations. A check valve is a mechanical device that permits fluid to flow, or pressure to act, one-way or in one direction only. Check valves are utilized in oil and gas industry applications, in particular involving fluid control and safety. Check valves can be designed for specific fluid types and operating conditions. Some designs are tolerant of debris, whereas others may obstruct the bore of the conduit or tubing in which the check valve is fitted. Conventional check valves are known to have reliability issues due to wear problems. This is a consequence of flow for an open valve continually passing both the seat and the sealing plug or ball of those check valves. These reliability issues lead to valve failure, particularly in abrasive flow applications or when larger objects flow through the valve. Oilfield operations can cause conventional pilots (mechanisms designed to restrict and guide fluid flow, e.g., poppet valves, ball valves, flapper valves, and chokes) to leak due to corrosion of the seat and valve during the operations. The use of check valves is important in the oil & gas industry as reliable check valves can protect against loss of well control, including well blowouts.
A check valve should be engineered to be operable in high stress and vibration environments, including casing operations in a wellbore that increase wear on the constituent valve components. The wear problem is compounded in abrasive environments, such as oilfield cements, muds or slurries.
In general, check valves are typically used immediately above the casing ends or joints in oilfield casing, and is typically termed a “float valve” or “float collar” respectively. While all components in a casing string are subject to relatively high vibrations, float valves are exposed to very high vibrations, including accelerations of up to 10 g (gravity) or more while flow passes, often in excess of 600 gallons per minute. Relative motion of the adjacent parts on wellbore equipment in the abrasive subterranean fluid environment increases wear on the wellbore equipment, which can cause misalignment between a sealing member of a valve and its valve seat.
Oil and gas operation check valves, as disclosed by U.S. Pat. Nos. 3,870,101, 6,401,824, 6,679,336, and U.S. Patent Application Nos. 2013/0082202 and 2014/0144526 utilize pilots to control fluid flow in high vibration oil and gas operations. However, these check valve devices suffer from corrosion on the seats and seals located inside the valves, due to the abrasive action of direct fluid flow as discussed above.
There is a need for a more reliable check valve that is designed to improve reliability by reducing corrosion from direct fluid flow on the seat and/or seals of the check valve.
Embodiments usable within the scope of the present disclosure meet these needs.